Sweet sorghum has become an important feedstock for bioethanol production. Total sugar yield and multiple harvests can directly affect ethanol production cost. Little is known about stem traits and multiple harvests t...Sweet sorghum has become an important feedstock for bioethanol production. Total sugar yield and multiple harvests can directly affect ethanol production cost. Little is known about stem traits and multiple harvests that contribute to sugar yield in sweet sorghum. Stem traits were evaluated from 25 sweet and grain sorghum accessions. Stems were harvested twice at the soft-dough stage and the stems were pressed with a hydraulic press. Sugars in the stem juice were quantified by high performance liquid chromatography. Sweet sorghum produced five times more fresh stem weight and dry stem mass (830 gand164 g) than grain sorghum (150 gand27g). Sweet sorghum produced a much higher volume of juice and higher yield of sugars (366 ml and42 g) per stem than grain sorghum (70 ml and4 g). Significant variability in fresh stem weight (72 - 1837 g), juice volume (31 - 753 ml), sugar yield (3 - 81 g), dry stem mass (14 - 383 g), and sugar yield/dry stem mass ratio (0.11 - 0.53) per stem was detected among sweet sorghum accessions. Stem sugar yield was significantly correlated with stem fresh weight and juice volume. Sorghum was harvested twice within one growing season resulting in some sweet sorghum accessions producing double amount of sugars. Sweet sorghum produced three times more dry mass weight (bagasse) than fermentable sugar weight. To reduce feedstock cost, methods have to be developed for efficiently utilizing bagasse. Our results showed high fresh stem weight, high ratio of sugar yield to dry stem mass, and double harvests are prime traits to boost sugar yield. Sweet sorghum may be suitable for multiple harvests in certain regions of theU.S.TheU.S.sweet sorghum collection needs to be screened for acces- sions that can be harvested twice with an extended feedstock-production season and used as a feedstock for sustainable and renewable bioenergy production.展开更多
A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well document...A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.展开更多
文摘Sweet sorghum has become an important feedstock for bioethanol production. Total sugar yield and multiple harvests can directly affect ethanol production cost. Little is known about stem traits and multiple harvests that contribute to sugar yield in sweet sorghum. Stem traits were evaluated from 25 sweet and grain sorghum accessions. Stems were harvested twice at the soft-dough stage and the stems were pressed with a hydraulic press. Sugars in the stem juice were quantified by high performance liquid chromatography. Sweet sorghum produced five times more fresh stem weight and dry stem mass (830 gand164 g) than grain sorghum (150 gand27g). Sweet sorghum produced a much higher volume of juice and higher yield of sugars (366 ml and42 g) per stem than grain sorghum (70 ml and4 g). Significant variability in fresh stem weight (72 - 1837 g), juice volume (31 - 753 ml), sugar yield (3 - 81 g), dry stem mass (14 - 383 g), and sugar yield/dry stem mass ratio (0.11 - 0.53) per stem was detected among sweet sorghum accessions. Stem sugar yield was significantly correlated with stem fresh weight and juice volume. Sorghum was harvested twice within one growing season resulting in some sweet sorghum accessions producing double amount of sugars. Sweet sorghum produced three times more dry mass weight (bagasse) than fermentable sugar weight. To reduce feedstock cost, methods have to be developed for efficiently utilizing bagasse. Our results showed high fresh stem weight, high ratio of sugar yield to dry stem mass, and double harvests are prime traits to boost sugar yield. Sweet sorghum may be suitable for multiple harvests in certain regions of theU.S.TheU.S.sweet sorghum collection needs to be screened for acces- sions that can be harvested twice with an extended feedstock-production season and used as a feedstock for sustainable and renewable bioenergy production.
文摘A late fall frost may significantly affect sugar crops’ stem sugar composition, yield and juice quality for biofuel and bioproduct manufacture. Research on the effects of late fall frost in sugarcane is well documented, but information is lacking for sweet sorghum. Three and six commercial cultivars of sugarcane and sweet sorghum, respectively, were selected and evaluated for exposure to a late fall frost (-2.8°C) in Griffin, Georgia, USA. Under the same controlled environmental conditions in a screen house, the late fall frost induced more damage to sugarcane than sweet sorghum stems. The frost caused damage to sugarcane tissue and for juice to exude from stems, whereas similar behavior was not observed for sweet sorghum. In both sugarcane and sweet sorghum, the glucose/fructose ratio was significantly reduced, but this change may not be totally directly related to the frost effect. Overall, these initial results suggest that sweet sorghum may have a better tolerance to fall frost than sugarcane. Two sweet sorghum cultivars, Grassl and M81E, responded well to the late fall frost, and they can possibly be used as feedstocks for biofuel/bioproduct manufacture in areas susceptible to frosts including northern regions of the Southeastern US.
